Native Development

[kboone]

Hi

Does anybody know if the time between screen taps that constitues a double-tap can be modified in a Qt application? Ideally, without modifying Qt itself Actually, modifying Qt isn't really a problem, since each application needs its own copy of the Qt libraries anyway. I just couldn't find where in the Qt code this was done. I'm not even sure whether Qt receives a specific double-tap event from the native event loop, or if it works out its own double-taps from the times between single-taps.

Best wishes

Kevin

[jheron]

Check the docs.

QApplication::setDoubleClickInterval

Cheers,

Jon

[kboone]

Thanks, but it didn't seem to make much difference for me. Does this method work for you?

To be honest, I have a suspicion that it's not the interval that makes the application seem insensitive to double-clicks, but how close together the screen taps have to be. I'm not sure what can be done about that.

[connyhald]

If thats the issue, try this. It woks for QML Listviews, Buttons, etc. Not sure it works for double-tap as well, though.

QApplication app(argc, argv);

// Because of the hi-res BB10 display be need a higher tolerance to mouse movements
app.setStartDragDistance(16);

[kboone]

Hi

Thanks. This does seem to help a bit.

Best wishes

Kevin

[trollixx]

I have the same problem, but using QApplication::setStartDragDistance() with high values isn't a good solution because it poors usability of Flickable-based components. So, I've done double tap handling on my own. Here's the code snippet, maybe you find it useful:

import QtQuick 1.1

Item {
    id: container

    signal clicked
    signal doubleClicked

    MouseArea {
        property double __clickTime: 0
        property int __mouseX: 0
        property int __mouseY: 0

        // Tune double tap here
        property int __doubleClickInterval: 400 // ms
    	property int __doubleClickDistance: 100 // px

        Timer {
            id: clickTimer
            interval: __doubleClickInterval
            onTriggered: {
                container.clicked()
                parent.__clickTime = 0
            }
        }

        onClicked: {
            // Handle single/double click on our own
            if (__clickTime === 0) {
                __clickTime = Date.now()
                clickTimer.start()
                __mouseX = mouse.x
                __mouseY = mouse.y
            } else if (Date.now() - __clickTime < __doubleClickInterval) {
                clickTimer.stop()
                __clickTime = 0
                if (Math.sqrt(Math.pow(__mouseX - mouse.x, 2) +
                        Math.pow(__mouseY - mouse.y, 2)) < __doubleClickDistance) {
                    container.doubleClicked()
                }
            }
        }

        anchors.fill: parent
    }
}